Methods and devices for sterilizing medical equipment

ABSTRACT

A hydrogen peroxide sterilization device for sterilizing a medical device, the hydrogen peroxide sterilization device including a hermetic outer container, a hydrogen peroxide pouch, and a hydrogen peroxide solution in the solution chamber. The hermetic outer container includes a sterilization enclosure configured to receive the medical device. The hydrogen peroxide pouch includes a permeable membrane enclosing a solution chamber and is configured to be positioned in the sterilization enclosure of the outer container. The permeable membrane is configured to allow hydrogen peroxide vapor to diffuse from the solution chamber through the permeable membrane into the sterilization enclosure.

RELATED APPLICATIONS

This application is a regular utility non-provisional application andclaims priority benefit of U.S. Provisional Patent Application Ser. No.63/012,580, entitled “METHODS AND DEVICES FOR STERILIZING MEDICALEQUIPMENT”, filed Apr. 20, 2020. The above-referenced provisionalapplication is hereby incorporated by reference in its entirety.

GOVERNMENT INTERESTS

This invention was made with Government support under Contract No.:DE-NA-0002839 awarded by the United States Department of Energy/NationalNuclear Security Administration. The Government has certain rights inthe invention.

BACKGROUND

Hydrogen peroxide is often used for sterilizing medical equipment,electronics, work surfaces, and common areas, but aqueous hydrogenperoxide solutions are undesirable because they require a sterilizeddevice or surface to be dried before use. Industrial machines are usedto convert hydrogen peroxide liquid into droplets, mist, and vapor forsterilizing large volumes such as cargo containers, hospital rooms, andoffice buildings, but that approach is not viable for sterilizingmedical devices in emergencies, in remote or isolated locations, duringtravel, or in one-off situations.

SUMMARY

Embodiments of the invention solve the above-mentioned problems andother problems and provide a distinct advancement in the art of medicalequipment sterilization. More particularly, the invention providesdevices and methods for sterilizing medical equipment via controlledhydrogen peroxide vapor delivery.

An embodiment of the invention is a hydrogen peroxide sterilizationdevice broadly comprising a hermetic outer container, a hydrogenperoxide pouch, an indicator, and a desiccant pouch. The hydrogenperoxide sterilization device is described in terms of sterilizing amedical face mask, but other medical devices, tools, and equipment mayalso be sterilized.

The hermetic outer container includes an outer wall and an openingsealing mechanism. The hermetic outer container may be molded to fit theitem being sterilized (similar to clamshell packaging) to reduce theamount of hydrogen peroxide vapor required to fill the space around theitem.

The outer wall forms a sterilization enclosure having an opening andretains water vapor and hydrogen peroxide vapor in the sterilizationenclosure. To that end, the outer wall may be polyethylene,polypropylene, metal, flouropolymers (perfluoroalkoxy alkanes (PFA),fluorinated ethylene propylene (FEP), etc. or any other suitablehermetic material.

The opening allows the user to insert the face mask and the hydrogenperoxide pouch into the sterilization enclosure. The opening may beclosed via the opening sealing mechanism.

The opening sealing mechanism is configured to be selectively opened forinserting the face mask into and removing the face mask from thesterilization enclosure. The opening sealing mechanism seals thesterilization enclosure when the opening sealing mechanism is closed.The opening sealing mechanism may be a zip-to-close mechanism, apress-and-seal mechanism, or any other suitable hermetic sealingmechanism.

The hydrogen peroxide pouch comprises a permeable membrane and ahermetic liner and forms a solution chamber. The hydrogen peroxide pouchis configured to be inserted into the sterilization enclosure with theface mask. In one embodiment, the hydrogen peroxide pouch is formed byheat sealing open sides of material. The solution chamber receiveshydrogen peroxide solution and may be 0.2 milliliters or any othersuitable volume. The solution chamber may be sealed or may be refillableand resealable.

The permeable membrane encloses the solution chamber and may be spunbonded polyethylene or any other suitable material configured to allowhydrogen peroxide vapor to diffuse out of the solution chamber into thesterilization enclosure. The permeable membrane may be heat sealed.

The hermetic liner encloses the permeable membrane and may be aplastic-lined metal pouch. For example, the hermetic liner may be a thinflexible plastic-lined foil. The hermetic liner is configured to preventthe hydrogen peroxide vapor from diffusing out of the solution chamberinto the sterilization enclosure unless the hermetic outer liner iscompromised via cutting, puncturing, tearing, or the like.

The hydrogen peroxide solution is a mixture of water and hydrogenperoxide. Hydrogen peroxide concentration may be between 1% and 100%(pure hydrogen peroxide with no water). In one embodiment, inhibitedhydrogen peroxide may be ACS reagent grade, between 10% and 35% (byweight).

The indicator reacts to hydrogen peroxide and identifies a concentrationor amount of hydrogen peroxide in the sterilization enclosure and/or thesolution chamber. To that end, the indicator may be located in thesterilization enclosure (e.g., on an inner surface of the hermetic outercontainer).

The desiccant pouch comprises a permeable membrane that includesactivated 3Å molecular sieves (desiccant) to control humidity within thesterilization enclosure. The molecular sieves lower the water vaporconcentration within the sterilization enclosure, thus allowing morehydrogen peroxide to enter the sterilization enclosure. The desiccantpouch is sealed in a hermetic liner to increase shelf-life. The hermeticliner encloses the permeable membrane and may be a plastic-lined metalpouch. For example, the hermetic liner may be a thin flexibleplastic-lined foil. The hermetic liner is configured to prevent thedesiccant from absorbing water vapor unless the hermetic outer liner iscompromised via cutting, puncturing, tearing, or the like.

In use, the face mask is placed in the sterilization enclosure of thehermetic outer container via its opening. The hermetic liner of thehydrogen peroxide pouch is then cut, torn, punctured, or at leastpartially removed. The hydrogen peroxide pouch is then placed in thesterilization enclosure with the face mask. The hermetic liner of thedesiccant pouch is then cut, torn, punctured, or at least partiallyremoved. The desiccant pouch is then placed in the sterilizationenclosure with the face mask. The opening sealing mechanism is thenclosed so that no vapor can diffuse out of the sterilization enclosure.

At least some of the hydrogen peroxide in the hydrogen peroxide solutionthen diffuses through the permeable membrane in the form of vapor intothe sterilization enclosure and sterilizes the face mask. To that end,the face mask and the hydrogen peroxide pouch may be retained in thesterilization enclosure for a predetermined or recommended amount oftime, until the face mask is needed again, until the hydrogen peroxidesolution has completely diffused into the sterilization enclosure, oruntil the indicator indicates a particular amount of hydrogen peroxidesolution has diffused into the sterilization enclosure.

The opening sealing mechanism is then opened, and the face mask isremoved from the hermetic outer container. The hydrogen peroxide pouchmay be discarded, refilled and resealed for future use, or reused ifsome of the hydrogen peroxide solution remains. To that end, thehydrogen peroxide pouch may be stored in the hermetic outer containeruntil the hydrogen peroxide sterilization device is used again.

The above-described hydrogen peroxide sterilization device providesseveral advantages. For example, the hydrogen peroxide pouch can besized to fit a large variety of enclosures and to accommodate a largerange of sterilization loads. Only a small quantity of hydrogen peroxideis needed for individual medical device sterilization, making thehydrogen peroxide sterilization device safe to use without training.Hydrogen peroxide concentrations can be adjusted to optimizesterilization and safety. The hydrogen peroxide pouch may be reusabledepending on the hydrogen peroxide concentration and active diffusiontime. In some embodiments, the hydrogen peroxide pouch is resealable.Off-the-shelf hermetic outer containers such as polyethylene bags can beused.

Another embodiment of the invention is a hydrogen peroxide sterilizationdevice broadly comprising a hermetic outer container and a hydrogenperoxide ampoule. The hydrogen peroxide sterilization device is similarto the hydrogen peroxide device described above except instead of ahydrogen peroxide pouch, the hydrogen peroxide ampoule delivers hydrogenperoxide vapor into the sterilization enclosure of the hermetic outercontainer.

The hydrogen peroxide ampoule comprises a glass tube and a permeablemembrane and forms a solution chamber. The hydrogen peroxide ampoule isconfigured to be inserted into the sterilization enclosure with themedical device. An open ended plastic sleeve covering the ampouleprotects the membrane from cutting when the ampoule is crushed. Thehydrogen peroxide ampoule may provide longer hydrogen peroxide shelflife.

The glass tube is a hermetic vessel that encloses the solution chamberand hence retains hydrogen peroxide solution in the solution chamber.The glass tube may be shattered or broken when sterilization is desired.

The permeable membrane encloses the glass tube and may be spun bondedpolyethylene or any other suitable material configured to allow hydrogenperoxide vapor to diffuse into the sterilization enclosure. Thepermeable membrane may be heat sealed.

In use, the face mask may be placed in the sterilization enclosure ofthe hermetic outer container via its opening. The hydrogen peroxideampoule may then be placed in the sterilization enclosure with the facemask. The hermetic liner of the desiccant pouch is then cut, torn,punctured, or at least partially removed. The desiccant pouch is thenplaced in the sterilization enclosure with the face mask. The openingsealing mechanism may then be closed so that no vapor can diffuse out ofthe sterilization enclosure. The glass tube of the hydrogen peroxideampoule may then be shattered or broken.

At least some of the hydrogen peroxide in the hydrogen peroxide solutionthen diffuses through the permeable membrane in the form of vapor intothe sterilization enclosure and sterilize the face mask. To that end,the face mask and the hydrogen peroxide ampoule may be retained in thesterilization enclosure for a predetermined or recommended amount oftime, until the face mask is needed again, or until the hydrogenperoxide solution has completely diffused into the sterilizationenclosure.

The opening sealing mechanism may then be opened, and the face mask maythen be removed from the hermetic outer container. The hydrogen peroxideampoule may then be discarded.

Another embodiment of the invention is a hydrogen peroxide sterilizationdevice broadly comprising a hermetic outer container and a hydrogenperoxide receptacle. The hydrogen peroxide sterilization device issimilar to the hydrogen peroxide devices described above except insteadof a hydrogen peroxide pouch or a hydrogen peroxide ampoule, thehydrogen peroxide receptacle delivers hydrogen peroxide vapor into thesterilization enclosure of the hermetic outer container.

The hydrogen peroxide receptacle includes a hermetic base vessel, apermeable lid, and a hermetic lid. The hydrogen peroxide receptacle maybe a closable bottle, a vile, a capsule, or any other suitable rigidreceptacle.

The hermetic base vessel is a rigid or minimally flexible containerforming a solution chamber. The hermetic base vessel may be made ofplastic, glass, ceramic, metal, or the like.

The permeable lid includes a permeable membrane and is configured to beremovably secured onto the hermetic base vessel to fully enclose thesolution chamber. To that end, the permeable lid may be snapped orcrimped onto the hermetic base vessel or attached to the hermetic basevessel via a fastener. Alternatively, the permeable lid (and/or hermeticbase vessel) may include helical threads for screwing the permeable lidon to the hermetic base vessel.

The permeable membrane may be spun bonded polyethylene or any othersuitable material configured to allow hydrogen peroxide vapor to diffuseout of the solution chamber. The permeable membrane may be heat sealed.

The hermetic lid is configured to be removably secured onto thepermeable lid or onto the hermetic base vessel over the permeable lid.To that end, the hermetic lid may be snapped or crimped onto thepermeable lid or hermetic base vessel or attached to the permeable lidor hermetic base vessel via a fastener. Alternatively, the hermetic lidmay include helical threads for screwing the hermetic lid onto thepermeable lid or hermetic base vessel.

In use, a face mask may be placed in the sterilization enclosure of thehermetic outer container via its opening. The hermetic lid and thepermeable lid may then be removed from the hermetic base vessel. Ahydrogen peroxide solution may then be poured into the hermetic basevessel. The permeable lid may then be secured onto the hermetic basevessel, thus sealing the hydrogen peroxide solution in the solutionchamber. The hydrogen peroxide receptacle may then be placed in thesterilization enclosure with the medical device. The opening sealingmechanism of the hermetic outer container may then be closed so that novapor can diffuse out of the sterilization enclosure

At least some of the hydrogen peroxide in the hydrogen peroxide solutionthen diffuses through the permeable membrane in the form of vapor intothe sterilization enclosure and sterilize the medical device. To thatend, the medical device and the hydrogen peroxide receptacle may beretained in the sterilization enclosure for a predetermined orrecommended amount of time (depending on the medical device or itsapplication), until the medical device is needed again, until thehydrogen peroxide solution has completely diffused into thesterilization enclosure, or until the indicator indicates a particularamount of hydrogen peroxide solution has diffused into the sterilizationenclosure.

The opening sealing mechanism may then be opened, and the medical devicemay then be removed from the hermetic outer container. The hydrogenperoxide receptacle may be discarded, refilled and resealed for futureuse, or reused if some of the hydrogen peroxide solution remains. Tothat end, the hydrogen peroxide receptacle may be stored in the hermeticouter container until the hydrogen peroxide sterilization device is usedagain.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

Embodiments of the present invention are described in detail below withreference to the attached drawing figures, wherein:

FIG. 1 is a perspective view of a hydrogen peroxide sterilization deviceconstructed in accordance with an embodiment of the invention;

FIG. 2 is a perspective view of a hydrogen peroxide sterilization deviceconstructed in accordance with another embodiment of the invention;

FIG. 3 is a receptacle of a hydrogen peroxide sterilization deviceconstructed in accordance with another embodiment of the invention; and

FIG. 4 is an alternative lid for use with the hydrogen peroxidesterilization device of FIG. 3 .

The drawing figures do not limit the present invention to the specificembodiments disclosed and described herein. The drawings are notnecessarily to scale, emphasis instead being placed upon clearlyillustrating the principles of the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The following detailed description of the invention references theaccompanying drawings that illustrate specific embodiments in which theinvention can be practiced. The embodiments are intended to describeaspects of the invention in sufficient detail to enable those skilled inthe art to practice the invention. Other embodiments can be utilized andchanges can be made without departing from the scope of the presentinvention. The following detailed description is, therefore, not to betaken in a limiting sense. The scope of the present invention is definedonly by the appended claims, along with the full scope of equivalents towhich such claims are entitled.

In this description, references to “one embodiment,” “an embodiment,” or“embodiments” mean that the feature or features being referred to areincluded in at least one embodiment of the technology. Separatereferences to “one embodiment,” “an embodiment,” or “embodiments” inthis description do not necessarily refer to the same embodiment and arealso not mutually exclusive unless so stated and/or except as will bereadily apparent to those skilled in the art from the description. Forexample, a feature, structure, act, etc. described in one embodiment mayalso be included in other embodiments, but is not necessarily included.Thus, the present technology can include a variety of combinationsand/or integrations of the embodiments described herein.

Turning to FIG. 1 , a hydrogen peroxide sterilization device 10 forsterilizing a medical device is illustrated. The hydrogen peroxidesterilization device 10 broadly comprises a hermetic outer container 12,a hydrogen peroxide pouch 14, an indicator 16, and a desiccant pouch 18.The hydrogen peroxide sterilization device 10 is shown sterilizing anexemplary medical device 100, which may be a face mask or any othermedical tool or personal health device.

The hermetic outer container 12 includes an outer wall 20 and an openingsealing mechanism 22. The hermetic outer container 12 may be molded tofit the item being sterilized (similar to clamshell packaging) to reducethe amount of hydrogen peroxide vapor required to fill the space aroundthe item. The hermetic outer container 12 may be a polyethylene bag, apolypropylene bag, or any other suitable hermetic container. Highdensity polyethylene provides an acceptable vapor barrier, whereas lowdensity polyethylene may be a poor barrier to oxygen and hydrogenperoxide.

The outer wall 20 forms a sterilization enclosure 24 having an opening26 and retains water vapor and hydrogen peroxide vapor in thesterilization enclosure 24. To that end, the outer wall 20 may bepolyethylene, polypropylene, or any other suitable hermetic material.The outer wall 20 may be transparent, thus allowing a user to observethe medical device 100 or personal health device without opening thehermetic outer container 12. The outer wall 20 may be flexible foraltering a volume of the sterilization enclosure 24.

The sterilization enclosure 24 receives the medical device 100 orpersonal health device and the hydrogen peroxide pouch 14 therein. Thesterilization enclosure 24 may be approximately one liter in maximumvolume or any other suitable size.

The opening 26 allows the user to insert the medical device 100 orpersonal health device and the hydrogen peroxide pouch 14 into thesterilization enclosure 24. The opening 26 may be closed via the openingsealing mechanism 22.

The opening sealing mechanism 22 is configured to be selectively openedfor inserting the medical device 100 or personal health device into andremoving the medical device 100 or personal health device from thesterilization enclosure 24. The opening sealing mechanism 22 seals thesterilization enclosure 24 when the opening sealing mechanism 22 isclosed. The opening sealing mechanism 22 may be a zip-to-closemechanism, a press-and-seal mechanism, or any other suitable hermeticsealing mechanism.

The hydrogen peroxide pouch 14 comprises a permeable membrane 28 and ahermetic liner 30 and forms a solution chamber 32. The hydrogen peroxidepouch 14 is configured to be inserted into the sterilization enclosure24 with the medical device 100 or personal health device. The hydrogenperoxide pouch 14 may be rectangular or any other suitable shape. In oneembodiment, the hydrogen peroxide pouch 14 is formed by heat sealingopen sides of material. For example, a Midwest Pacific Impulse HeatSealer model MP-12 set on 3.8 may effectively heat seal the hydrogenperoxide pouch 14. The hydrogen peroxide pouch 14 may have an area of100 cm² or any other suitable area. The solution chamber 32 receiveshydrogen peroxide solution 34 and may be 0.2 milliliters or any othersuitable volume. The solution chamber 32 may be sealed or may berefillable and resealable.

The permeable membrane 28 encloses the solution chamber 32 and may bespun bonded polyethylene, such as Tyvek brand, or any other porousmaterial, such as Gore-Tex brand, configured to allow hydrogen peroxidevapor to diffuse out of the solution chamber 32 into the sterilizationenclosure 24. The permeable membrane 28 may be heat sealed. Thepermeable membrane 28 may be transparent, thus allowing a user toobserve an amount of hydrogen peroxide solution 34 in the hydrogenperoxide pouch 14.

In one embodiment, the permeable membrane 28 may be 0.006 inches thickand made from 50 gram/meter² spun bonded polyethylene fabric. Goodtransport of hydrogen peroxide vapor occurs as the fabric isapproximately two-thirds void space, since 0.006 inch thick solidpolyethylene film weighs 141 gram/meter². The high surface area of thefabric also allows for more efficient vaporization of hydrogen peroxide.Other spun bonded fabrics such as polypropylene or polyester having asimilar void volume may also be used.

The hermetic liner 30 encloses the permeable membrane 28 and may be aplastic-lined metal pouch. For example, the hermetic liner 30 may be athin flexible plastic-lined foil, to allow for it to be heat sealed. Thehermetic liner 30 is configured to prevent the hydrogen peroxide vaporfrom diffusing out of the solution chamber 32 into the sterilizationenclosure 24 unless the hermetic outer liner 30 is compromised viacutting, puncturing, tearing, or the like. To that end, the hermeticliner 30 may have a crease, crimp line, or notch for facilitating acompromising action.

The hydrogen peroxide solution 34 may be a mixture of water and hydrogenperoxide, such as the inhibited hydrogen peroxide solution supplied bySigma Aldrich. Hydrogen peroxide concentration may be between 1% and100% (pure hydrogen peroxide with no water). In one embodiment, hydrogenperoxide may be ACS reagent grade, between 10% and 35% (by weight). Inanother embodiment, ACS reagent grade, 30% (by weight) hydrogen peroxidesolution may be used. The hydrogen peroxide solution 34 may be betweenapproximately 100 milliliters to approximately 500 milliliters. Forextended shelf life, the hydrogen peroxide solution 34 may be packagedin glass ampoules within the hydrogen peroxide pouch 14 and broken whenready for use. The hydrogen peroxide solution 34 may be shipped in abottle made of high-density polyethylene.

The indicator 16 reacts to hydrogen peroxide and identifies aconcentration or amount of hydrogen peroxide in the sterilizationenclosure 24 and/or the solution chamber 32. The indicator 16 may be anindicator strip such as an XploSens PS. In one embodiment, the indicator16 has a range of 0-500 ppm and turns orange when exposed to saturatedwater/hydrogen peroxide vapor at room temperature. The indicator 16 maybe located in the sterilization enclosure 24 (e.g., on an inner surfaceof the hermetic outer container 12). In other words, the indicator 16may be located anywhere that alerts a user to an amount of vapordiffusion in the hydrogen peroxide pouch 14. If more precise hydrogenperoxide concentration monitoring is required, a probe such as a VaisalaHPP272 hydrogen peroxide, humidity, and temperature probe may be used.Detection range of the above probe is 0 ppm to 2,000 ppm.

The desiccant pouch 18 includes a permeable membrane 36 and a hermeticliner 38 and holds activated 3 Å molecular sieves 40 (desiccant) tocontrol humidity within the sterilization enclosure 24. The molecularsieves 40 lower the water vapor concentration within the sterilizationenclosure 24, thus allowing more hydrogen peroxide to enter thesterilization enclosure 24. Without the desiccant, the water andhydrogen peroxide vapor quickly saturate the air in the sterilizationenclosure 24, thus preventing further vaporization of water and hydrogenperoxide. Hydrogen peroxide molecules are slightly larger than watermolecules, resulting in the preferential uptake of water molecules bythe desiccant. In one embodiment, 6 grams of desiccant may be used. Thedesiccant pouch 18 may be a spun bonded polyethylene pouch with a metalfoil outer packaging to prevent moisture uptake until needed.

The permeable membrane 36 encloses the molecular sieves 40 and may bespun bonded polyethylene or any other suitable material configured toallow water vapor to pass into the desiccant pouch 18 and be absorbed bythe molecular sieves 40. The permeable membrane 36 may be heat sealed.

The hermetic liner 38 encloses the permeable membrane 36 and may be athin flexible plastic-lined metal foil. The hermetic liner 38 preventsthe molecular sieves 40 from absorbing water unless the hermetic liner38 is compromised via cutting, puncturing, tearing, or the like. Assuch, the hermetic liner 38 increases shelf life of the molecular sieves40.

Use of the hydrogen peroxide sterilization device 10 will now bedescribed. First, the medical device 100 or personal health device maybe placed in the sterilization enclosure 24 of the hermetic outercontainer 12 via its opening 26. The hermetic liner 30 of the hydrogenperoxide pouch 14 may then be cut, torn, punctured, or at leastpartially removed. The hermetic liner 38 of the desiccant pouch 18 mayalso be cut, torn, punctured, or at least partially removed. Thehydrogen peroxide pouch 14 and desiccant pouch 18 may then be placed inthe sterilization enclosure 24 with the medical device 100 or personalhealth device. The opening sealing mechanism 22 may then be closed sothat no vapor can diffuse out of the sterilization enclosure 24. In oneembodiment, a dry gas may be added to the sterilization enclosure 24before it is closed to increase the diffusion of hydrogen peroxide vaporthrough the permeable membrane 28.

At least some of the hydrogen peroxide in the hydrogen peroxide solution34 will then diffuse through the permeable membrane 28 in the form ofvapor into the sterilization enclosure 24 and sterilize the medicaldevice 100 or personal health device. To that end, the medical device100 or personal health device and the hydrogen peroxide pouch 14 may beretained in the sterilization enclosure 24 for a predetermined orrecommended amount of time (depending on the medical device 100 orpersonal health device or its application), until the medical device 100or personal health device is needed again, until the hydrogen peroxidesolution 34 has completely diffused into the sterilization enclosure 24,or until the indicator indicates a particular amount of hydrogenperoxide solution 34 has diffused into the sterilization enclosure 24.

The opening sealing mechanism 22 may then be opened, and the medicaldevice 100 or personal health device may then be removed from thehermetic outer container 12. The hydrogen peroxide pouch 14 may bediscarded, refilled and resealed for future use, or reused if some ofthe hydrogen peroxide solution 34 remains. To that end, the hydrogenperoxide pouch 14 may be stored in the hermetic outer container 12 untilthe hydrogen peroxide sterilization device 10 is used again.

A test of the above concepts was performed via 1.0 liter Nalgene highdensity polyethylene bottles, which showed significantly higherconcentrations of hydrogen peroxide vapor than low density polyethylenebags. In addition to being made of HDPE, the Nalgene bottle is muchthicker at 0.060 inches compared to 0.0015 inches for an LLDPE bag.Since hydrogen peroxide vapor containment is an important aspect of theinvention, materials having low oxygen transmission rates are desirable.Examples include aluminum foil, metalized polyester, perfluoroalkoxyalkanes (PFA), fluorinated ethylene propylene (FEP), metalizedpolyethylene terephthalate (Mylar), ethylene vinyl alcohol (EVOH), andpolyvinylidene chloride.

Similarly, ½ gallon and 1 gallon HDPE Nalgene bottles were evaluated,with maximum hydrogen peroxide concentration shown in Table 1 below.Each containment vessel held two Du Pont Sierra masks, size 7 inch, Partnumber ML 7330BU000500BH, and 6 grams of 3 Å molecular sieves. Maximumhydrogen peroxide vapor concentrations were achieved within 6 hours to 8hours after start of the test and gradually declined to zero over a 24hour period.

TABLE 1 HP loading RS Vessel size Material μ liters PPM (%) (1) 1 galbag LLDPE 250 211  8.1 1 gal bag (2) LLDPE 300  96 71.9 1 liter bottleHDPE 250 945 23.9 1 liter HDPE 250 1292  65.9 bottle (3) 1 liter bottleHDPE 300 1004  80.4 1 liter bottle HDPE 300 1045  87.4 ½ gal bottle HDPE300 928 34.2 ½ gal bottle HDPE 300 822 34.4 1 gal bottle HDPE 500 67062.1 1 gal bottle HDPE 500 724 58.3 1 gal bag FEP 400 698 56.5 ½ gal bagPET metalized 300 528 44.7 ½ gal bag PFA 400 558 26.9 (1) RelativeSaturation (RS)—indicates the humidity of the air caused by both HP andwater vapor (2) Run terminated early (3) No masks inside

The above-described hydrogen peroxide sterilization device 10 providesseveral advantages. For example, the hydrogen peroxide pouch 14 can besized to fit a large variety of enclosures and to accommodate a largerange of sterilization loads. Only a small quantity of hydrogen peroxideis needed for individual medical device sterilization, making thehydrogen peroxide sterilization device 10 safe to use without training.Hydrogen peroxide concentrations can be adjusted to optimizesterilization and safety. More than one hydrogen peroxide membrane pouchcan be used for large enclosures. The hydrogen peroxide pouch 14 may bereusable depending on the hydrogen peroxide concentration and activediffusion time. In some embodiments, the hydrogen peroxide pouch 14 isresealable. Off-the-shelf hermetic outer containers such as polyethylenebags or pails can be used.

Turning to FIG. 2 , a hydrogen peroxide sterilization device 200constructed in accordance with another embodiment of the inventionbroadly comprises a hermetic outer container 202 and a hydrogen peroxideampoule 204. The hydrogen peroxide sterilization device 200 is shownsterilizing an exemplary medical device 206, which may be a face mask orany other medical tool or personal health device. The hydrogen peroxidesterilization device 200 may also include an indicator and a desiccantpouch as described above.

The hermetic outer container 202 includes an outer wall 208 and anopening sealing mechanism 210. The hermetic outer container 202 may bemolded to fit the item being sterilized (similar to clamshell packaging)to reduce the amount of hydrogen peroxide vapor required to fill thespace around the item. The hermetic outer container 202 may be apolyethylene bag, a polypropylene bag, or any other suitable hermeticcontainer. High density polyethylene provides an acceptable vaporbarrier, whereas low density polyethylene may be a poor barrier tooxygen and hydrogen peroxide.

The outer wall 208 forms a sterilization enclosure 212 having an opening214 and retains water vapor and hydrogen peroxide vapor in thesterilization enclosure 212. To that end, the outer wall 208 may bepolyethylene, polypropylene, or any other suitable hermetic material.The outer wall 208 may be transparent, thus allowing a user to observethe medical device 206 or personal health device without opening thehermetic outer container 202. The outer wall 208 may be flexible foraltering a volume of the sterilization enclosure 212.

The sterilization enclosure 212 receives the medical device 206 and thehydrogen peroxide ampoule 204 therein. The sterilization enclosure 212may be approximately one liter in maximum volume or any other suitablesize.

The opening 214 allows the user to insert the medical device 206 orpersonal health device and the hydrogen peroxide ampoule 204 into thesterilization enclosure 212. The opening 214 may be closed via theopening sealing mechanism 210.

The opening sealing mechanism 210 is configured to be selectively openedfor inserting the medical device 206 or personal health device into andremoving the medical device 206 or personal health device from thesterilization enclosure 212. The opening sealing mechanism 210 seals thesterilization enclosure 212 when the opening sealing mechanism 210 isclosed. The opening sealing mechanism 210 may be a zip-to-closemechanism, a press-and-seal mechanism, or any other suitable hermeticsealing mechanism.

The hydrogen peroxide ampoule 204 comprises a glass tube 216 and apermeable membrane 218 and forms a solution chamber 220. The hydrogenperoxide ampoule 204 is configured to be inserted into the sterilizationenclosure 212 with the medical device 206. The hydrogen peroxide ampoule204 may provide longer hydrogen peroxide shelf life.

The glass tube 216 is a hermetic vessel that encloses the solutionchamber 220 and hence retains hydrogen peroxide solution in the solutionchamber 220. The glass tube 216 may be shattered, broken, crushed,punctured, or snapped (without puncturing the permeable membrane 218),when sterilization is desired.

The permeable membrane 218 encloses the glass tube 216 and may be aplastic sleeve with open or permeable ends, spun bonded polyethylene,such as Tyvek brand, or any other porous material, such as Gore-Texbrand, configured to allow hydrogen peroxide vapor to diffuse into thesterilization enclosure 212. The permeable membrane 218 may be heatsealed. The permeable membrane 218 may be transparent, thus allowing auser to observe an amount of hydrogen peroxide solution in the glasstube 216.

The hydrogen peroxide solution may be a mixture of water and hydrogenperoxide, such as the hydrogen peroxide solution supplied by SigmaAldrich. Hydrogen peroxide concentration may be between 1% and 100%(pure hydrogen peroxide with no water). In one embodiment, inhibitedhydrogen peroxide may be ACS reagent grade, between 10% and 35% (byweight). In another embodiment, ACS reagent grade, 30% (by weight)hydrogen peroxide solution may be used. The hydrogen peroxide solutionmay be between approximately 100 milliliters to approximately 500milliliters.

Use of the hydrogen peroxide sterilization device 200 will now bedescribed. First, the medical device 206 may be placed in thesterilization enclosure 212 of the hermetic outer container 202 via itsopening 214. The hydrogen peroxide ampoule 204 may then be placed in thesterilization enclosure 212 with the medical device 100. The openingsealing mechanism 210 may then be closed so that no vapor can diffuseout of the sterilization enclosure 212. The glass tube 216 of thehydrogen peroxide ampoule 204 may then be shattered or broken.

At least some of the hydrogen peroxide in the hydrogen peroxide solutionwill then diffuse through the permeable membrane 218 in the form ofvapor into the sterilization enclosure 212 and sterilize the medicaldevice 206. To that end, the medical device 206 and the hydrogenperoxide ampoule 204 may be retained in the sterilization enclosure 212for a predetermined or recommended amount of time, until the medicaldevice 206 is needed again, or until the hydrogen peroxide solution hascompletely diffused into the sterilization enclosure 212

The opening sealing mechanism 210 may then be opened, and the medicaldevice 206 may then be removed from the hermetic outer container 202.The hydrogen peroxide ampoule 204 may then be discarded.

Turning to FIG. 3 , a hydrogen peroxide sterilization device 300constructed in accordance with another embodiment of the inventionbroadly comprises a hermetic outer container and a hydrogen peroxidereceptacle 302. The hermetic outer container is substantially similar tothe hermetic outer containers described above and will not be describedfurther.

The hydrogen peroxide receptacle 302 includes a hermetic base vessel304, a permeable lid 306, and a hermetic lid 308. The hydrogen peroxidereceptacle 302 may be a closable bottle, a vile, a capsule, or any othersuitable rigid receptacle.

The hermetic base vessel 304 may be a rigid or minimally flexiblecontainer forming a solution chamber 310. The hermetic base vessel 304may be made of plastic, glass, ceramic, metal, or the like. The hermeticbase vessel 304 may be transparent, thus allowing a user to observe anamount of hydrogen peroxide solution in the hydrogen peroxide receptacle302. In one embodiment, the hermetic base vessel 304 also includes anindicator (e.g., a specific gravity indicator sphere) configured toidentify a concentration or amount of hydrogen peroxide in the solutionchamber 310.

The permeable lid 306 may include a permeable membrane 312 and isconfigured to be removably secured onto the hermetic base vessel 304 tofully enclose the solution chamber 310. To that end, the permeable lid306 may be snapped or crimped onto the hermetic base vessel 304 orattached to the hermetic base vessel 304 via a fastener. Alternatively,the permeable lid 306 (and/or hermetic base vessel 304) may includehelical threads for screwing the permeable lid 306 on to the hermeticbase vessel 304.

The permeable membrane 312 may be spun bonded polyethylene, such asTyvek brand or, any other porous material, such as Gore-Tex brand,configured to allow hydrogen peroxide vapor to diffuse out of thesolution chamber 310. If the hermetic base vessel 304 is polyethylene,polypropylene or other thermoplastic the permeable membrane 312 may beheat sealed.

The hermetic lid 308 is configured to be removably secured onto thepermeable lid 306 or onto the hermetic base vessel 304 over thepermeable lid 306. To that end, the hermetic lid 306 may be snapped orcrimped onto the permeable lid 306 or hermetic base vessel or attachedto the permeable lid 306 or hermetic base vessel 304 via a fastener.Alternatively, the hermetic lid 308 may include helical threads forscrewing the hermetic lid 308 onto the permeable lid 306 or hermeticbase vessel 304. In one embodiment, the hermetic base vessel 304 mayship with the hermetic lid 308 and when ready for use, the permeable lid306 is secured to the hermetic base vessel 304 with the hermetic lid308.

Alternatively, as shown in FIG. 4 , a permeable lid 400 including asecurement rim 402 and a permeable membrane 404 may be used with thehermetic base vessel 304. The securement rim 402 and permeable membrane404 may be a single component. For example, the securement rim 402 maybe polypropylene with the permeable membrane 402 being fused to thesecurement rim 402.

Use of the hydrogen peroxide sterilization device 300 will now bedescribed. A medical device may be placed in the sterilization enclosureof the hermetic outer container via its opening. The hermetic lid 308and the permeable lid 306 may then be removed from the hermetic basevessel 304. A hydrogen peroxide solution may then be poured into thehermetic base vessel 304. The permeable lid 306 may then be secured ontothe hermetic base vessel 304, thus sealing the hydrogen peroxidesolution in the solution chamber 310. The hydrogen peroxide receptacle302 may then be placed in the sterilization enclosure with the medicaldevice. The opening sealing mechanism of the hermetic outer containermay then be closed so that no vapor can diffuse out of the sterilizationenclosure. In one embodiment, a dry gas may be added to thesterilization enclosure before it is closed to increase the diffusion ofhydrogen peroxide vapor through the permeable membrane 312.

At least some of the hydrogen peroxide in the hydrogen peroxide solutionwill then diffuse through the permeable membrane 312 in the form ofvapor into the sterilization enclosure and sterilize the medical device.To that end, the medical device and the hydrogen peroxide receptacle 302may be retained in the sterilization enclosure for a predetermined orrecommended amount of time (depending on the medical device or itsapplication), until the medical device is needed again, until thehydrogen peroxide solution has completely diffused into thesterilization enclosure, or until the indicator indicates a particularamount of hydrogen peroxide solution has diffused into the sterilizationenclosure.

The opening sealing mechanism may then be opened, and the medical devicemay then be removed from the hermetic outer container. The hydrogenperoxide receptacle 302 may be discarded, refilled and resealed (i.e.,the hermetic lid 308 may be secured over the permeable lid or replacedif in case of threaded solution chamber 310) for future use, or reusedif some of the hydrogen peroxide solution 34 remains. To that end, thehydrogen peroxide receptacle 302 may be stored in the hermetic outercontainer until the hydrogen peroxide sterilization device 300 is usedagain.

The above-described hydrogen peroxide sterilization device 300 providesseveral advantages in addition to the advantages described above. Forexample, the hydrogen peroxide receptacle 302 can be sized to fit alarge variety of enclosures and to accommodate a large range ofsterilization loads. The hydrogen peroxide receptacle 302 is easy torefill and can be safely stored in a portable first aid kit or medicalcart. The permeable lid 306 and hermetic lid 308 allow the hydrogenperoxide receptacle 302 to be stored, used, and refilled by removing orsecuring the permeable lid 306 and/or the hermetic lid 308. To thatpoint, no liner tearing, cutting, or puncturing is required, which isdifficult for frail users and could lead to user injury.

Although the invention has been described with reference to theembodiments illustrated in the attached drawing figures, it is notedthat equivalents may be employed and substitutions made herein withoutdeparting from the scope of the invention as recited in the claims.

Having thus described various embodiments of the invention, what isclaimed as new and desired to be protected by Letters Patent includesthe following:

The invention claimed is:
 1. A hydrogen peroxide sterilization devicefor sterilizing a medical device, the hydrogen peroxide sterilizationdevice comprising: a hermetic outer container having a sterilizationenclosure configured to receive the medical device, the hermetic outercontainer being a high density polyethylene, perfluoroalkoxy alkanes(PFA), fluorinated ethylene propylene (FEP), metalized polyethyleneterephthalate (Mylar), or metal; a hydrogen peroxide pouch comprising: apermeable membrane enclosing a solution chamber at least partiallyfilled with a hydrogen peroxide solution, the permeable membrane beingformed of spun bonded polyethylene and configured to allow hydrogenperoxide vapor to diffuse from the solution chamber through thepermeable membrane into the sterilization enclosure, and a hermeticouter liner enclosing the permeable membrane, the hermetic outer linerbeing a plastic-lined metal pouch and configured to prevent the hydrogenperoxide vapor from diffusing out of the solution chamber into thesterilization enclosure unless the hermetic outer liner is compromised,the hydrogen peroxide pouch being configured to be positioned in thesterilization enclosure of the outer container and being refillable andresealable so that hydrogen peroxide solution remaining in the solutionchamber is retained in the solution chamber when the hydrogen peroxidepouch is resealed; and an indicator configured to identify aconcentration or amount of hydrogen peroxide solution in the solutionchamber or a concentration or amount of hydrogen peroxide vapor in thesterilization enclosure.
 2. The hydrogen peroxide sterilization deviceof claim 1, further comprising a dry gas in the sterilization enclosureto promote diffusion of the hydrogen peroxide vapor through thepermeable membrane.
 3. The hydrogen peroxide sterilization device ofclaim 1, further comprising a desiccant pouch including activatedmolecular sieves configured to reduce humidity in the sterilizationenclosure.
 4. The hydrogen peroxide sterilization device of 3, thedesiccant pouch further including a permeable membrane and a hermeticouter liner enclosing the permeable membrane, the hermetic outer linerbeing configured to prevent the activated molecular sieves fromabsorbing water out of the sterilization enclosure unless the hermeticouter liner is compromised.
 5. The hydrogen peroxide sterilizationdevice of claim 1, the indicator being configured to react to thehydrogen peroxide vapor in the sterilization enclosure.
 6. The hydrogenperoxide sterilization device of claim 1, the indicator being anindicator strip.
 7. The hydrogen peroxide sterilization device of claim1, the hermetic outer container including an inner surface, theindicator being positioned on the inner surface.